This invention relates to an integrated circuit having a semiconductor component.
The commutation of inductive loads at low-side switches (dissipation of the energy of the coil load after the switch-off of the transistor) is generally effected by means of an active voltage limiting at the low-side switch. FIG. 6 shows by way of example a circuit arrangement in accordance with the prior art for the commutation of an inductive load L, in which a DMOS power transistor 1 is used as a low-side switch.
In this exemplary embodiment, the inductive load L is connected on one end side to a line 3 carrying operating potential. The other side of the load L is connected to a drain input D of the DMOS power transistor. A source input of the DMOS transistor is connected to a ground connection 2. A zener diode chain 4 having the zener diodes Z1, Z2, Z3 and, respectively, Z4 and acting as a voltage divider is in each case situated between the drain D and gate G and, respectively, a gatesource resistance RGS, which turn on the low-side transistor 1 when the potential rises at the drain D.
Besides the loading during commutation, low-side switches protect themselves dependent on size up to a certain loading by electrostatic discharges (ESD) according to HBM (acronym for Human Body Model).
In view of the increasingly more stringent requirements made of the ESD durability at the IC level (acronym for integrated circuit), for instance given by the requirement for protection against pistol discharges according to IEC standard (discharge network approximately 150 pF and 330Ω compared with 1.5 kΩ and 100 pF in the case of HBM; standards: IEC 61000-4-2, JESD 22-A114-B), a self-protection of the low-side switch by means of active zenering is increasingly difficult to impossible depending on the required endurance with respect to pistol discharges. However, the protection of the low-side switch against ESD loading has to be safeguarded by means of a separate ESD structure. However, this is at odds with the requirement of commutation by means of the low-side switch since either the ESD structure or the active voltage limiting (active clamping) of the zener chain circuit accepts the loading both during commutation and in the ESD case.